Patent GB-1260331-A (GB)
Title: Improvements relating to fastening devices
Inventor: MYATT KEITH ERNEST
IPC: F16B21/02
Filed: 1969-02-01
Abstract: 1,260,331. Releasable fasteners. G.K.N. SCREWS & FASTENERS Ltd. 20 Jan., 1970 [1 Feb., 1969], No. 5581/69. Heading E2B. A releasable fastener for holding together apertured first and second members 46, 62 comprises a turn piece 10 having a shank 13, a head 14 at one end of the shank and a fasten ing projection 20 adjacent the other end of the shank, a retaining piece 11 to be assembled to the first member and having an aperture to receive the shank being adapted to hold the turn piece captive on first member while allowing the turn piece to rotate relative to the retaining piece and having means 35 to engage the first member to prevent rotation of the retaining piece relative thereto, a cam piece 12 to be assembled to the second member and having an aperture to receive the shank and the fastening projection, a cam surface 60 to engage the projection upon turning of the turn piece after the projection has passed through the aperture to draw the shank through the aperture and means 51 to engage the second member to prevent rotation of the cam piece relative thereto, the retaining piece and/or the cam piece comprising a cup 27 or 47 having a base and a side wall, the base having said shank receiving aperture therein and the side wall having an outwardly directed flange 33 or 50 at the free edge thereof, a ring 48 or 28 having an outwardly directed flange 43 or 54 and the ring and the cup having complementary formations that of the cup being adjacent its base to enable the ring to be engaged with and disengaged from the cup by a snap action and spring means 16 to assist the drawing of the shank through the aperture. In the embodiment shown both the retaining piece and the cam piece consist of a cup and a ring the complementary formations being a groove in the cup and a rib of the ring (52, 53 are shown) and both the cam piece and the retaining piece are intended to engage members which are comparatively thick and which are shown as being of multilayered corrugated paper board construction. For fastening together two said members one of which is thinner than the other, either the retaining piece or cam piece of cup and ring form is replaced by a one element piece; the one element form of retaining piece is shown in Fig. 7 the retaining piece including a flange 66 and two parts of 71 depending from the flange which form a split bushing which has a bore 73 to receive the shank of the turn piece and which can be snapped through an aperture in the member to which it is to be engaged the member being received in a groove 75. Rotation of the piece is prevented by a lug 78 which engages a hole in the member. The cam piece which can replace the two element cam piece is similar to the retaining piece shown in Fig. 7 except that the projecting parts are formed with the cam surfaces for engaging the pair of projections 20 shown. The spring means is a resilient conical skirt depending from the head of the turn piece which serves to hold the two projections 20 in detents 61 in the projections which provide the cam surfaces, the head also has a bore to receive a spigot 22 of a handle member 21 by means of which the turn piece can be rotated. The shank of the turn piece has flats 18 which engage flats 41 of the retaining piece to hold the turn piece in two positions 90‹ apart.